A drum continuous miner (CM) is a machine used for underground mining of ore seams. A typical CM includes a frame propelled by tracked drive units. The frame supports a power source (e.g., an electric motor) and a milling drum. The milling drum, fitted with cutting tools, is rotated through a suitable interface by the power source to break up an exposed surface of the ore seam. The broken up material is deposited by the milling drum onto a conveyor for removal from an underside of the CM to a rear end of the CM. The material is then transferred from the conveyor into a nearby haul vehicle for transportation away from the worksite.
The milling drum is generally supported at spaced apart locations by vertically oriented struts. In particular, the milling drum can be divided into three or five different segments, with a strut located between adjacent segments. The struts vertically support the milling drum, and also provide a way to drive the milling drum. For example, a shaft, a belt, or a chain can pass from the electric motor through the strut to the milling drum, thereby engaging an end of each drum segment to rotate the drum. Because the cutting surface of the milling drum is segmented at the struts, a vertical core of unmilled material may be left at each strut location. These cores, if left intact, can inhibit further penetration of the CM into the ore material. Accordingly, the cores must be periodically broken off and moved out of the way of the struts.
An exemplary continuous mining machine is disclosed in U.S. Pat. No. 8,511,757 of O'Neill that issued on Aug. 20, 2013 (“the '757 patent”). Specifically, the '757 patent discloses a mining machine having a core breaker. The core breaker is positioned between the cutting drums of the mining machine, and includes a circular beveled blade having a plurality of bits that can break the core material into fragments. The beveled blade is forced into the core material by forward motion of the mining machine. By breaking the core material into fragments, the barrier to further penetration of the milling drum into the ore seam is eliminated.
Although the core breaker of the '757 patent may be beneficial in removing the vertical core left between adjacent segments of a milling drum, the core breaker may be less than optimal. In particular, a force necessary to push the core breaker into the material core may be significant, requiring the mining machine to be large and heavy and to have an engine or motor with significant power. A large, heavy mining machine may be inefficient, and the size of the engine or motor required to move the machine may have poor efficiency and be expensive to purchase and to operate.
The disclosed mining machine and core cutting assembly may be directed at overcoming one or more of the problems set forth above and/or other problems in the prior art.